(Systena frontalis (Fabricius)) and Smartweed (S. hudsonias) are common in the east but rarely found to the west of there. They are voracious, polyphagous herbivores of both crops and weeds. Due to their affinity for weeds as well, crop protection must include weed management. The Southern tobacco flea beetle (Epitrix fasciata Blatchley) is found along the Gulf Coast. Aeronautics Lyndon B. Johnson Space Center, the center of the National Aeronautics and Space Administration (NASA), is located in Houston. It is a leading hub for the Aeronautics industry. The National Space and Biomedical Research Institute is headquartered in Houston. Dallas/Fort Worth International Airport, located nearly equidistant from downtown Dallas and downtown Fort Worth, is the largest airport in the state, the second-largest in the US, and the fourth-largest in the world. In terms of traffic, DFW is the busiest in the state, the third-busiest in the nation, and the sixth-busiest in the world. The airport serves 135 domestic destinations and 40 international. DFW is the largest and main hub for American Airlines, one of the world's largest in terms of total passengers-miles transported and passenger fleet size. Texas's second-largest air facility is Houston's George Bush Intercontinental Airport (IAH), the largest hub of United Airlines. IAH offers service to the most Mexican destinations of any U.S. airport. IAH is currently ranked second among all U.S. airports with scheduled non-stop domestic and international service. Headquartered in Fort Worth, American Airlines is the world's largest airline by passenger miles, passengers carried, and revenue. Southwest Airlines, also a leader in the commercial passenger market, is based near Love Field airport in Dallas. Lockheed Martin Aeronautics, the aviation division of Lockheed Martin, is also headquartered in Fort Worth, and the company's Missiles and Fire Control division is based in nearby Grand Prairie, along with the American division of Airbus Helicopters, Airbus Helicopters, Inc. Bell Helicopter is headquartered in Fort Worth as well. Defense Texas is home to two of the United States Army's largest facilities (in terms of geographic size), Fort Hood in Central Texas near Killeen and Fort Bliss near El Paso. In addition, Fort Sam Houston in San Antonio is home to the Brooke Army Medical Center, one of the Army's major hospitals and its only burn facility, and the Corpus Christi Army Depot in Corpus Christi, Texas is home to the world's largest helicopter repair and maintenance facility. The United States Air Force